A Green Approach to 2-Substituted Benzo- and Naphthothiazoles via <i>N</i>-bromosuccinimide/Bromide-Mediated C(aryl)-S Bond Formation

Abstract

2-Substituted benzo- and naphthothiazoles have been conveniently prepared from the intramolecular cyclization of phenylthioureas and activated thiobenzanilides or the coupling of isothiocyanates with amines under mild conditions using N-bromosuccinimide/tetrabutylammonium bromide in 1,2-dimethoxyethane (DME) under ambient conditions. The reactions produce moderate to excellent yields with good functional group tolerance and avoid the use of harsh thermal conditions, corrosive reagents, halogenated solvents, toxic metal salts, and expensive metal catalysts, and are amenable to preparations on a gram-scale.

Keywords

• 2-aminobenzothiazole
• benzothiazole
• <i>N</i>-bromosuccinimide
• naphthothiazole
• oxidative cyclization
• phenylthiourea